The structure of kidneys.

**Introduction: *Every day, Human kidneys filter nearly 200 liters of fluid from the blood stream, Allowing (i.e. permit) toxins, metabolic wastes, and excess ions, to leave the body in urine,  while returning the needed substances to the blood. 

Although lungs and skin also participate in excretion, but the kidneys are the major excretory organs….*So, in spite of, the kidneys perform these excretory functions, they also act as essential regulators of the volume(i.e. blood volume) and chemicals[hormones]makeup of the blood {RBCs}.. i.e. *Maintaining the proper balance between “Water + Salts” and between “acids + bases”  in body fluids (blood)

 There by,  Other renal functions include:

*Gluconeogenesis…….. i.e,  Production of glucose…

*Production of hormones{Renin}, i.e. a protein hormone or enzyme, that regulate the blood pressure and also Erythropoietin hormone, that stimulates production of RBCs….

And finally: metabolizing “Vitamin-D” to its active form.

Besides the urine-forming kidneys, the urinary system include:

****Urinary bladder…

****Paired ureters…[Right & Left]

***&,  Urethra…….